Tractor having dual hydrostatic drive with single hand control and attachment adapter for powered attachments

Abstract

A tractor has a base for supporting a motive power source, left and right driven wheels, and left and right transmissions for the respective left and right wheels. A handle structure is coupled to the base for grasping by an operator from behind the tractor. A drive system drives each of the left and right transmissions with motive power from the motive power source. A single lever hand control is provided for operation by a single hand of the operator for controlling both left and right transmissions seamlessly each between reverse speed through neutral and forward speed.

What is claimed is: 
     
       1. A tractor comprising:
 a base for supporting a motive power source, left and right driven wheels having a wheel axis and left and right hydrostatic transmissions for the respective left and right wheels; 
 a handle structure coupled to the base for grasping by an operator who walks behind the tractor; 
 a drive system for driving each of the left and right transmissions with motive power from the motive power source, further wherein there is a longitudinally disposed space between the left and right transmissions; 
 further comprising a power take off shaft disposed in the longitudinally disposed space extending anteriorly and driven by the motive power source for powering a powered attachment adapted to be disposed at the anterior of the tractor; 
 further comprising a power take off adapter disposed at an anterior location on said tractor having a power coupling driven by said power take off shaft, said adapter allowing the operator to connect and disconnect a powered attachment by manipulating handles of the handle structure of the tractor from an operator's position by pivoting the handles in a vertical direction about the wheel axis; 
 said power coupling being attached to the power take off shaft, said power take off adapter comprising a front mounted adapter plate, said power coupling extending out of an opening in said front mounted adapter plate; 
 said power coupling being adapted to engage a mating coupling on a receiver plate of a powered attachment; 
 further comprising an alignment structure on the adapter plate for causing said power coupling to align laterally and vertically with the mating coupling of the powered attachment as the adapter plate is moved by pivoting the handles in the vertical direction about the wheel axis; 
 said alignment structure being arranged to allow the weight of the tractor to be used to cause the power coupling and mating coupling to align and engage; 
 further comprising a locking structure for locking said engaged power coupling and mating coupling together. 
 
     
     
       2. The tractor of  claim 1 , wherein said alignment structure comprises a set of rails facing anteriorly inclined toward each other on said adapter plate that engage with rails on the receiver plate for forcing said power coupling and mating coupling into alignment through manipulation of said tractor. 
     
     
       3. A tractor comprising:
 a base for supporting a motive power source, left and right driven wheels and left and right hydrostatic transmissions for the respective left and right wheels; 
 a handle structure coupled to the base for grasping by an operator who walks behind the tractor: 
 a drive system for driving each of the left and right transmissions with motive power from the motive power source, 
 further wherein there is a longitudinally disposed space between the left and right transmissions; 
 further comprising a power take off shaft disposed in the longitudinally disposed space extending anteriorly and driven by the motive power source for powering a powered attachment adapted to be disposed at the anterior of the tractor; 
 further comprising a power take off adapter disposed at an anterior location on said tractor having a power coupling driven by said power take off shaft, said adapter allowing the operator to connect and disconnect a powered attachment by manipulating handles of the handle structure of the tractor from an operator's position; 
 wherein said power coupling is attached to the power take off shaft, said power take off adapter comprising a front mounted adapter plate, said power coupling extending out of an opening in said front mounted adapter plate; 
 said power coupling being adapted to engage a mating coupling on a receiver plate of a powered attachment; 
 further comprising an alignment structure on the adapter plate for causing said power coupling to align with the mating coupling of the powered attachment; 
 said alignment structure being arranged to allow the weight of the tractor to be used to cause the power coupling and mating coupling to align and engage; 
 further comprising a locking structure for locking said engaged power coupling and mating coupling together; 
 wherein said alignment structure comprises a set of rails facing anteriorly inclined toward each other on said adapter plate that engage with rails on the receiver plate for forcing said power coupling and mating coupling into alignment through manipulation of said tractor; 
 wherein the inclined rails have top edges inclined rearwardly forming a hook for engaging a horizontal top pin of the receiver plate and having bottom edges that are rounded to allow a horizontal bottom pin of the receiver plate to slide beneath the bottom edges; 
 further wherein the power coupling is slidable on a spline on the power take off shaft and spring loaded so as to be biased to engage the mating coupling. 
 
     
     
       4. The tractor of  claim 3 , wherein the locking structure comprises a hook that is movable forward and aft and vertically by the operator, thereby to allow the hook to be moved over the bottom horizontal pin of the receiver plate by the vertical motion of the hook and the receiver plate to be drawn against the adapter plate by the aft motion of the hook. 
     
     
       5. The tractor of  claim 4 , further comprising an operator control on the handle structure for controlling the forward and aft motion and vertical motion of the hook. 
     
     
       6. The tractor of  claim 1 , further comprising a power take off clutch coupled to an output shaft of said motive power source, said clutch being selectively engageable by a user to power said power take off shaft. 
     
     
       7. The tractor of  claim 6 , further comprising a first pulley at an output of said clutch and a further pulley on said power take off shaft driven by a power take off drive belt between said pulleys. 
     
     
       8. The tractor of  claim 7 , further comprising a second pulley on the output of said clutch driving a transmission drive belt, said transmission drive belt driving said left and right transmissions. 
     
     
       9. The tractor of  claim 1 , wherein the tractor is a walk-behind tractor. 
     
     
       10. A tractor comprising:
 a base for supporting a motive power source, left and right driven wheels having a wheel axis and a transmission for driving the left and right wheels; 
 a handle structure coupled to the base for grasping by an operator who walks behind the tractor; 
 a drive system for driving the transmission with motive power from the motive power source, 
 further comprising a power take off shaft extending anteriorly and driven by the motive power source for powering a powered attachment disposed at the anterior of the tractor, 
 further comprising a power take off adapter disposed at an anterior location on said tractor having a power coupling driven by said power take off shaft, said adapter allowing a the operator to connect and disconnect a powered attachment by manipulating handles of the handle structure of the tractor from an operator's position by pivoting the handles in a vertical direction about the wheel axis; 
 said power take off adapter comprising a front mounted adapter plate, said power coupling extending out of an opening in said front mounted adapter plate; 
 said power coupling being adapted to engage a mating coupling on a receiver plate of a powered attachment; 
 further comprising an alignment structure on the adapter plate for causing said power coupling to align laterally and vertically with the mating coupling of the powered attachment as the adapter plate is moved laterally and vertically by pivoting the handles in the vertical direction about the wheel axis; 
 said alignment structure being arranged to allow the weight of the tractor to be used to cauae the power coupling and mating couplin to align and engage; 
 further comprising a locking structure for locking said engaged power coupling and mating coupling together. 
 
     
     
       11. The tractor of  claim 10 , wherein said alignment structure comprises a set of rails facing anteriorly inclined toward each other on said adapter plate that engage with rails on the receiver plate for forcing said power coupling and mating coupling into alignment through manipulation of said tractor. 
     
     
       12. A tractor comprising:
 a base for supporting a motive power source, left and right driven wheels and a transmission for driving the left and right wheels; 
 a handle structure coupled to the base for grasping by an operator who walks behind the tractor; 
 a drive system for driving the transmission with motive power from the motive power Source, 
 further comprising a power take off shaft extending anteriorly and driven by the motive power source for powering a powered attachment disposed at the anterior of the tractor, 
 further comprising a power take off adapter disposed at an anterior location on said tractor having a power coupling driven by said power take off shaft, said adapter allowing the operator to connect and disconnect a powered attachment by manipulating handles of the handle structure of the tractor from an operator's position; 
 said power take off adapter comprising a front mounted adapter plate, said power coupling extending out of an opening in said front mounted adapter plate; 
 said power coupling being adapted to engage a mating coupling on a receiver plate of a powered attachment; 
 further comprising an alignment structure on the adapter late for causing said power coupling to align with the mating coupling of the powered attachment; 
 said alignment structure being arranged to allow the weight of the tractor to be used to cause the power coupling and mating coupling to align and engage; 
 further comprising a locking structure for locking said engaged power coupling and mating coupling together; 
 wherein said alignment structure comprises a set of rails facing anteriorly inclined toward each other on said adapter plate that engage with rails on the receiver plate for forcing said power coupling and mating coupling into alignment through manipulation of said tractor; 
 wherein the inclined rails have top edges inclined rearwardly forming a hook for engaging a horizontal top pin of the receiver plate and having bottom edges that are rounded to allow a horizontal bottom pin of the receiver plate to slide beneath the bottom edges; 
 further wherein the power coupling is slidable on a spline on the power take off shaft and spring loaded so as to be biased to engage the mating coupling. 
 
     
     
       13. The tractor of  claim 12 , wherein the locking structure comprises a hook that is movable forward and aft and vertically by the operator, thereby to allow the hook to be moved over the bottom horizontal pin of the receiver plate by the vertical motion of the hook and the receiver plate to be drawn against the adapter plate by the aft motion of the hook. 
     
     
       14. The tractor of  claim 13 , further comprising an operator control on the handle structure for controlling the forward and aft motion and vertical motion of the hook. 
     
     
       15. The tractor of  claim 10 , further comprising a power take off clutch coupled to an output shaft of said motive power source, said clutch being selectively engageable by a user to power said power take off shaft. 
     
     
       16. The tractor of  claim 15 , further comprising a first pulley at an output of said clutch and a further pulley on said power take off shaft driven by a power take off belt between said pulleys. 
     
     
       17. The tractor of  claim 16 , further comprising a second pulley on the output of said clutch driving a transmission drive belt, said transmission drive belt driving said transmission. 
     
     
       18. The tractor of  claim 10 , wherein the operator manipulates the handles to orient the tractor to align the adapter plate and receiver plate and pivots the tractor to cause the weight of the tractor to force the adapter plate into alignment with the receiver plate and the power coupling and mating coupling to align and engage. 
     
     
       19. The tractor of  claim 10 , wherein the tractor is a walk-behind tractor. 
     
     
       20. A tractor comprising:
 a base for supporting a motive power source, left and right driven wheels having a wheel axis and a transmission for driving the left and right wheels; 
 a handle structure coupled to the base for grasping by an operator who walks behind the tractor; 
 a drive system for driving the transmission with motive power from the motive power source, 
 further comprising a power take off shaft extending anteriorly and driven by the motive power source for powering a powered attachment disposed at the anterior of the tractor, 
 further comprising a power take off adapter disposed at an anterior location on said tractor having a power coupling driven by said power take off shaft, said adapter allowing the operator to connect and disconnect a powered attachment by manipulating handles of the handle structure of the tractor from an operator's position by pivoting the handles in a vertical direction about the wheel axis; 
 said power take off adapter comprising a front mounted adapter plate, said power coupling extending out of an opening in said front mounted adapter plate; 
 said power coupling being adapted to engage a mating coupling on a receiver plate of a powered attachment; 
 further comprising an alignment structure for causing said power coupling to align laterally and vertically with the mating coupling of the powered attachment as the adapter plate is moved laterally and vertically by pivoting the handles in the vertical direction about the wheel axis; 
 said alignment structure being arranged to allow the weight of the tractor to be used to cause the power coupling and mating coupling to align and engage; 
 further comprising a locking structure for locking said engaged power coupling and mating coupling together. 
 
     
     
       21. The tractor of  claim 20 , wherein the alignment structure comprises a set of rails facing anteriorly inclined toward each other on said adapter plate that engage with rails on the receiver plate for forcing said power coupling and mating coupling into alignment through manipulation of said tractor.